The Listen module enables an intelligent robot to simulate
hearing in humans. There are two important considerations here
for programmers who wish to port the AI to other languages, or
to enhance the sufficient but minimal complexity of the AI Mind.

2. To Listen Is To Be Event-Driven

In the language that you choose for re-implementing the structures
of the Robot AI Mind, it is quite essential that you find a way topoll the keyboard for human input without stopping the AI program,
that is, without forcing the aLife routine to stop thinking while
passively waiting for the input which may or may not be coming.
Your AI program will need to include either a feature of letting the
user interrupt the robot thought processes, or a subroutine which
waits for an arbitrarily brief time to see if anyone is communicating.

The second consideration is that robot AI programs must eventually
improve the AI algorithm and use speech recognition to capture and
record the actual phonemes of human speech.

The JavaScript code for Listen and the Forth code for Listen
are quite different because JavaScript is event-driven, while
Forth must actually take time out to check for human input.

When the input to Mind.Forth is actually the reentry of its output,
Mind.Forth bypasses the Listen module and feeds Speech data directly
into the Audition module, obviating the need for a Reentry module.

The AI source code (q.v.) of the Listen module records keystrokes
coming in from the human user. A more advanced AI may use speech
recognition to process and store phonemes.

The Listen function is so quintessentially passive that it
lends itself to an astronomically (think: SETI) enormous range
of situations and applications. The event to trigger the AI
may be specified so strictly and so exceptionally that the
MTBA (mean time between alerts) might stretch on for years.

Imagine being able to walk anywhere inside a large building
while an AI Mind listens attentively for the slightest word
issuing uniquely from your lips in your own unmistakable voice.
You are free to roam, while the building maintenance AI or the
guardian angel AI is on high alert through a vast audio network.

Now imagine a SETI AI that listens to the cosmos in ways unthinkable
to even the most sophisticated human being. Because only the event
of alien contact triggers the AI, no AI effort is expended.